This invention relates to improved manual actuators for use in conjunction with automatic electrohydraulic devices for operating a valve, damper or other controlled element.
Powered actuators have been devised in the past for moving a controlled part within a predetermined range of movement in accordance with variations in an input signal delivered to the device. In some such arrangements, the power for moving the controlled element is supplied by a pressurized fluid, delivered by a pump or other pressure fluid source, and acting to move a power piston relative to a cylinder in correspondence with variations in an electrical control signal. An electrohydraulic actuator of this type is disclosed in our copending application Ser. No. 321,444 filed Nov. 16, 1981 on "Double Acting Linear Actuator".